| Several types of rigid beam-clumn connections used in hight seidmic region will be recommended by presently revised Technical specification for steel structure of tall buildings (JGJ99), which the welded flange plate connection (WFP) and cover plate connection (CP) are the main connection types. The aim of experiment in this paper is to provide the reference date for revising the specification.Seven 1/2 scale model of MRP connections were tested in the paper, included four welded flange plate types, one cover-plate type, one welded flange-bolted web and one fully weld connectional types. The material of specimens was Q345B steel and the welding electrode was E5015. The speciments were designed and detailed in terms of Chinese code for design of steel structures (GB50017), Chinese technical specification for steel structure of tall buildings (JGJ99), Chinese code for seismic design of buildings (GB50011) and the procedures of secommended seismic design criteria for new Steel moment-frame buildings (FEMA 350). The leading design idea for reinforced type is to move plastic hinge outward from the interface of beam end to column flange. For WFP connection, the flange plate was welded to beam flange by fillet welds, and welded to column flange by butt welds, while the beam flange was free to column flange. For CP connection, the cover plate and beam flange were weld to column flange using a single butt welds, and cover plate was welded to beam flange by fillet welds. Rectangular reinforced plates were used in the tests. Welded flange-bolted web and welded flange-welded web connections failed in a brittle manner, beam flange was tore in heat affected zone, and the performance of latter was better than the former. All of the reinforced connections can ensure the plastic hinge moving outward from the interface of beam end to column flange, none of them failed in a brittle manner;and the strength of each connection degraded slowly due to plastic deformation and local buckling of the beam web and flange. The maximum beam plastic hinge rotations ranged from 0.020radto 0.024rad for welded flange-bolted web and welded flange-welded web connection, while for reinforced ones ranged from 0.044rad to 0.054rad. The cover-plate and flange-plate connections performanced equally well in the tests. None of reinforced plates buckled locally or failed in the tests. Beam flange was susceptible to buckling with the increase of its width-to-thickness, but its influence on bearing capacity of connection was less;while the influence on bearing capacity was larger, with the increase of the height-to-thickness ratio of beam web;And the bearing capacity decreased obviously which weaker panel zone,while its deformation capacity increased remarkablely.After the analysis test, finite element analysis was carried out to compare with the test results. In general, they agreed well in bearing capacity, rigidity degeneration, and stress distribution. At the end of the paper, suggestions were put forward according to the test results, which might be referenced to revise the specification. |
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